The U.S. space agency NASA says its Phoenix probe has touched the surface of the planet Mars with its robot arm.

Officials said Sunday that operators were testing the arm, which will be used to scoop up samples of Martian soil and ice for testing in the lander's onboard laboratory.

NASA released a photograph of the disturbed soil where the arm touched the ground, leaving behind a footprint-shaped impression. A camera attached to the arm also took photographs of the area beneath the lander.

The Phoenix probe arrived on Mars a week ago. It is on a three-month mission to analyze samples of Martian soil and subsurface ice, to study the history of water on Mars and to determine whether the planet could support life.

Phoenix was launched last August and traveled 679 million kilometers to reach Mars.

Some information for this report was provided by AP.